(CNN) — Microsoft’s public experiment with artificial intelligence apparently needs a major tune-up. The tech company designed a chat bot to talk on social media like a teenager, activating it on Twitter on Wednesday. However, less than a day later, the A.I., named Tay, started spewing racist and hateful comments. Microsoft shut Tay down around midnight, deleted most of the offensive tweets. They have yet to release a comment on the matter. Instead, in her last tweet, Tay said she needed sleep and hinted that she would be back.